Integrated process for effectively recovering oil from tar sands



Dec l, 1964 J. A. BICHARD E'rAl.. 3 159 562 INTEGRATED FRocEss FoR FFFECTIVELY RRcovRRrNG on. FRoM TAR sANDs Filed sept. 7, 1961 John A Bichard James w lwunder/ Invenfcrs B y w 7W Potent- Attorney :55 R wPZwEmJm @z X-E 05k/ N Il j N) R s w. .m W )ANEj/EAJE C 7 MXN l. E E I Em R w n z mwefl |=O IM* n oOh w Km) A (n, k

United States Patent() 3,19,562 HNTTEGRATED PlP-.QCESS FR EFFECTEVELY RECGWERHJG @EL FRM TAR SANDS lohn A. Prichard, Point Edward, Untario, and .lames W.

Wunder, Sarnia, Qatar-io, Canada, assignors to Esso Research and Engineering Company, a corporation of Delaware Filed Sept. 7, 196i, Ser. No. 136,521 6 Claims. (Cl. 208-11) The present invention is broadly concerned with the recovery of hydrocarbons from tar sands. The invention is more particularly concerned with an improved technique of efliciently removing hydrocarbons, such as bitumen, tars, and the like from tar sands containing the same, such as Athabaska tar sands. The invention is particularly concerned with an improved integrated process for the recovery of oil from tar sands wherein in one operation or an initial phase, at relatively low temperatures, the process comprises removing substantially oil-free sand from a quantity of tar sands as mined, thereby increasing the concentration of the tar or bitumen on the remaining sands. The bitumen-rich sand is then further handled in `a secondary phase utilizing steam and relatively high temperatures in order to produce an oil phase containing a relatively small amount of sand.

In various areas of the world, tar sands exist which contain Various types of hydrocarbons as, for example, the heavy deposits of Athabaska tar sands existing in Canada. These sands contain tremendous reserves of hydrocarbon constituents. For example, the oil in the sands may vary from about 5% to 21% by volume, generally in the range of about 12% by volume. The gravity of the oil ranges from about 6 to 10 API, generally about 8 API. These sands may lie from about 200 to 300 feet below an overburden and the beds may range from about 100 to 400 feet thick. A typical oil recovered from the sands has an initial boiling point of about 300 F., 1.0% distilled to 430 F., 20.0% distilled to 650 F. and 50.0% distilled to 980 F. However, the recovery of hydrocarbons in the past has not been effective to any great extent due to the deficiencies in operating techniques for the recovery of these hydrocarbons. For example, ya relatively small amount of clay (from about to 30%, usually about in the sand greatly retards recovery of the oil utilizing conventional water techniques. Apparently the oil and the clay form skins which envelop small pockets of water often containing nely divided sand; then the enveloped pockets are distributed in water, thus forming a type of emulsion.

Numerous attempts have been made in the past to recover bitumen from the Athabaska tar sands in various manners. For example, it has been suggested that a solvent be added in order to reduce the viscosity of the bitumen, and in conjunction with water, to oat the bitumen solvent mixture away from the sand. Although this technique achieves a good separation of clean sand, the addition of water results in problems with the formation of stable emulsions and sludges which have been very difficult to separate. Thus, extensive supplementary processing has been required in order to avoid large oil losses.

It has also been suggested in the past that tar sands as they are mined be handled by a thermal process in order to recover the bitumen therefrom. However, this process has been uneconomical due to the large amount of heat which is lost due to the fact that the heat is imparted to the sand and cannot be effectively and efficiently recovered therefrom. It has been suggested for example that tar sands be handled in a direct lluid coking operation. However, as pointed out, this process is uneconomical for the reasons given above. Also, any process that will effective- 3,l50,562 Patented Dec. 1, 1964 ly handle tar sands must have the ability to handle a very wide range of tar sand and compositions which occur even in an immediate location. Some processes as, for example, direct fluid coking are able to handle these widely different compositions and, in accordance with the present process, employing a two-phase operation wherein in an initial phase a substantially richened tar sand is produced and wherein in the second phase the enriched sand is for example handled in a fluid coker, surprisingly effective results are secured.

The present invention may be readily understood by reference to the drawing illustrating the same. The figure illustrates the integrated process of the present invention wherein two phases are illustrated. In the iirst phase of the operation, enriched sands are produced using relatively low temperatures and, in the second phase ofthe operation, the enriched sands are handled at relatively high temperatures in order to produce an oil phase containing a relatively small amount of sand.

Referring specically to the ligure illustrating an integrated process, tar sands as mined are introduced into a shearing-mixing stage or zone 3 of the sand separation phase by means of line 1. Water is introduced by means of line 2 and mixed with the sands. This water may be introduced directly into the shearing-mixing zone 3. It is also to be understood that while only one mixing zone is illustrated, a plurality of shearing-mixing zones may be used and a plurality of injection points also utilized. As a specific example, the composition of the sand introduced into zone 3 comprises about 6% by weight connate water, 15% by weight of bitumen, about 80% by weight of sand and about 5% clay. The clay content varies from about 0 to 30% in these sands but, in the specific example given, the clay comprises about 5% by weight of the total.

The mixing operation in zone 3 is carried out under conditions wherein a shearing thrust is imparted to the sands being mixed with the added water. Under these conditions, substantially oil-free sands separate and the entire mixture is then passed into the second stage or zone of the sand separation phase which preferably comprises a mechanical separation zone 5. The sands are introduced into zone 5 by means of line d.

This mechanical separation zone may comprise any suitable mechanical means for separating the substantially oil-free sands from the bitumen-rich sands. For example, the mixture introduced by means of line 4 may be sieved in order to separate the oil-free sand which oilfree sand is removed by means of line 1l. The bitumen enriched sands in a plastic physical state are removed by means of line 6 and passed into the second phase of the integrated process which comprises a relatively high temperaturel operation. Stages 3 and 5 are preferably conducted at temperatrues in the range from about 32 to F., preferably at temperatures in the range from 50 to 90 P. It is also preferred that the amount of water utilized in stages 3 and 5' be in the range from about 40 to 400% of water by weight, preferably in the range from 40 to 150% of water by weight based upon the tar sands being processed.

Under the conditions of the present process, the oil phase removed from stage 5 by means of line 6 contains from about 30 to 50% of oil. This phase is introduced into separation zone l0 which preferably comprises a pug mill wherein steam is injected by means of line 20. It is to be understood that the steam may be introduced at a plurality of points. Zone l0 may be any desirable type of pug mill as, for example, one which contains mixing elements 21 at the bottom thereof with paddles in order to remove the sand countercurrent to the introduction of the feed stream. The sand stream is removed by means of line 22.

The temperature in zone 10 is maintained in the range from about 140 to 210 F., preferably at a temperature in the range from about 185 to 195 F. The amount of steam introduced into zone is adjusted so that there exists in this zone to 160% of water, preferably 30 to 100% of water by Weight based upon the oil present.

The mixed oil phase is withdrawn from pug mill 10 by means of line 7 and introduced into a separation zone 15. ln this zone an oil phase 23 formed on the top which is removed by means of line 8. Sand collects in the lower area of zone or cell 15 and is removed by means of line 9. In accordance with the present adaptation, steam and/or water is introduced into cell 15 by means of lines 12 and 13 and air by means or line 14 in order to bring the sand in a r'luidized condition. A plurality of addition points may be used. In order to further illustrate the invention the following exaaple is given.

Example In one operation, a sand containing 6% by weight of connate water, 15% by weight of bitumen, 80% by weight of sand and about 5% clay was processed in zones 3 and 5 at a temperature of about 70 l?. in a manner as described.

The oil phase removed from zone 5 comprised 34% by weight of oil, 13% by weight of water, and 53% by weight of sand. This feed was introduced into zone 1t? at a temperature of 190 F. under conditions where approximately 40 to 100% by weight of water is present.

The streams were then introduced into zone 15 maintained at a temperature of about 190 F. and an oil phase removed by means of line 8 and a sand phase by means of line 9. Under these conditions of operation, the oil phase removed by means of line 8 comprised 70% by weight of oil, by weight of water, and 5% by weight of sand on a wet basis. The oil content was 93.2% by weight, while the sand was 6.8% by weight on a dry basis. In the same operation, the sand removed by means of line 9 contained less than about 0.2% by weight of oil.

Thus, the present invention is concerned with a twophase operation wherein in the first phase tar sands are subjected to shearing-mixing agglomeration action at relatively low temperatures, and in a second phase the oil phase is treated at a relatively high temperature utilizing injected steam and air. Under these conditions of operation, the oil phase is relatively pure and substantially no oil is lost in the sand phase.

What is claimed is:

1. Improved process for producing bitumen oil from natural tar sands which comprises adding a fluid consisting essentially of water to natural sands and in an initial stage subjecting the mixture to a mixing-shearing action at a temperature in the range from about 50 to F., whereby relatively oil-free sands and oil-rich sands are produced, removing the enriched sands from the relatively oil-free sands and subjecting the enriched sands in a second stage to a temperature in the range from about to 210 F. in the presence of steam, thereafter passing the heated mixture to a separation zone and separating an oil-rich phase and a sand phase.

2. Process as dcned by claim 1 wherein about 40% to 400% by weight, based upon dry bitumen sands, of water is added to said natural sands in said initial stage.

3. Process as delined by claim 2 wherein the quantity of water added is in the range from about 40% to about 4. Process as dened by claim 1 wherein the temperature in the initial phase is in the range from about 50 to 90 F. and wherein the temperature in the second phase is about to 195 F.

5. Process for producing bitumen oil from natural tar sands which comprises adding from about 40-150% by weight of a fluid consisting essentially of water to natural tar sands and in an initial stage, subjecting the mixture to a mixing-shearing action at a temperature in the range from about 50-90 F., whereby relatively oil-free sands and oil-enriched sands are produced, removing the enriched sands from the relatively oil-frce sands and subjecting the enriched sands in a second stage to a temperature in the range from about 140-200 F. in the presence of steam, the amount of steam added being of the magnitude so as to maintain about 30-100% by weight of water present, thereafter passing the heated mixture to a third stage wherein additional quantities of steam are added, and separating an oil phase substantially free of sand from said third stage.

6. Process as defined by claim 5 wherein air is also added in said third stage.

References Cited in the file of this patent UNTTED STATES PATENTS 1,514,162 Kelsey Nov. 4, 1-924 1,520,752 Horwitz Dec. 30, 1924 1,594,796 Rockwell Aug. 3, 1926 2,453,060 Bauer et al. Nov. 2, 1948 2,825,677 Coulson Mar. 4, 1958 FOREIGN PATENTS 586,229 Canada Nov. 3, 1959 

1. IMPROVED PROCESS FOR PRODUCING BITUMEN OIL FROM NATURAL TAR SANDS WHICH COMPRISES ADDING A FLUID CONSISTING ESSENTIALLY OF WATER TO NATURAL SANDS AND IN AN INITIAL STAGE SUBJECTING THE MIXTURE TO A MIXING-SHEARING ACTION AT A TEMPERATURE IN THE RANGE FROM ABOUT 50* TO 110*F., WHEREBY RELATIVELY OIL-FREE SANDS AND OIL-RICH SANDS ARE PRODUCED, REMOVING THE ENRICHED SANDS FROM THE RELATIVELY OIL-FREE SANDS AND SUBJECTING THE ENRICHED SANDS IN A SECOND STAGE TO A TEMPERATURE IN THE RANGE FROM ABOUT 140* TO 210*F. IN THE PRESENCE OF STEAM, THEREAFTER PASSING THE HEATED MIXTURE TO A SEPARATION ZONE AND SEPARATING AN OIL-RICH PHASE AND A SAND PHASE. 